Structure for supporting swash plate of variable displacement swash plate type compressor

ABSTRACT

A structure for supporting a swash plate of a variable displacement swash plate type compressor is disclosed. The structure has a spherical sleeve slidably mounted on the drive shaft, a journal mounted on an outer surface of the sleeve and inserted in the swash plate, and a pair of pins adapted to connect the journal to the sleeve. An external diameter of the sleeve is smaller than an internal diameter of the journal, so that a predetermined gap is provided therebetween. Since the sleeve and the journal are not in contact with each other but connected to each other by the pins, a precise machining operation of the facing surfaces thereof and an additional machining operation for flat surfaces are not necessary, thereby facilitating machining of the sleeve and the journal. Lubrication therebetween is also not necessary.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a swash plate type compressorfor use in an air conditioning for vehicles, and, more particularly, toa variable displacement swash plate type compressor having a structurecapable of supporting a swash plate while enabling adjustment of theswash plate with respect to a drive shaft.

[0003] 2. Description of the Related Technology

[0004] A swash plate type compressor adapted to be predominantly used inan air conditioning for vehicles is constructed such that a disc-shapedswash plate, which is obliquely mounted on a drive shaft for receivingpower from an engine, is rotated by the drive shaft, and a plurality ofpistons coupled to a peripheral portion of the swash plate through shoesare linearly reciprocated in associated cylinder bores formed in acylinder block by a rotation of the swash plate to cause refrigerant gasto be inhaled, compressed and exhausted.

[0005] A variable displacement swash plate type compressor has a swashplate, which is mounted on a drive shaft to be varied in its inclinedangle according to thermal load, so that reciprocating amounts ofpistons are varied to cause refrigerant compression amount to becontrolled.

[0006] In FIG. 1, there is shown an example of such a variabledisplacement swash plate type compressor disclosed in Japanese patentLaid-open No. H 11-125176.

[0007] As shown in the drawing, the variable displacement swash platetype compressor includes a cylinder block 1 having a plurality ofcylinder bores 1 a, which are longitudinally disposed at its peripheralportion and are parallel to each other, a front housing 2 hermeticallyconnected to a front end of the cylinder block 1, and a rear housing 3hermetically connected to a rear end of the cylinder block 1 through avalve plate 3 a.

[0008] A crank chamber 4 defined by the front housing 2 is centrallyprovided with a drive shaft 5 which passes through the center of thefront housing 2 and is rotatably supported by the front housing 2. A rugplate 6 and a swash plate 7 are rotatably mounted on the drive shaft 5.The rug plate 6 is adapted to be rotated together with the drive shaft5. The swash plate 7 is mounted on the drive shaft 5 to be inclined at apredetermined angle. The swash plate 7 is coupled at its end to the rugplate 6 by means of a hinge means 8 so that the swash plate 7 is rotatedtogether with the rug plate 6 while axially sliding along the driveshaft 5 to enable its incline angle to be varied.

[0009] The swash plate 7 is connected at its peripheral portion to aplurality of pistons 9 through shoes 10 at a certain spacing. Theplurality of pistons 9 are reciprocated in the cylinder bores 1 arespectively.

[0010] The rear housing 3 is provided with an intake chamber 11 and anexhaust chamber. A valve plate 3 a is formed with an intake opening 13and an exhaust opening 14.

[0011] In the drawing, reference numerals 15 and 16, which are notexplained, denote an intake reed valve and a discharge reed valveadapted to open and close the intake opening 13 and the exhaust opening14 of the valve plate 3 a, respectively, reference numeral 17 denotes aspring interposed between the rug plate 6 and the swash plate 7 forbiasing the swash plate 7 with respect to the rug plate 6. A controlvalve(not shown) is adapted to operatively communicate the crank chamber4 and the intake chamber 11 for varying differential pressure betweenrefrigerant pressure in the cylinder bore 1 a and gas pressure in thecrank chamber 4, thereby causing an incline angle of the swash plate tobe controlled.

[0012] Such this type of variable displacement swash plate typecompressor is constructed such that the pistons 9, which are slidablyconnected to the swash plate 7, are reciprocated by the swash plate 7repeatedly moving back and forth while rotating together with the driveshaft 5 to cause refrigerant to be compressed, and the inclined angle ofthe swash plate 7 is controlled according to differential pressurebetween pressure in the crank chamber 4 and the cylinder bores la tocause exhaust amount of the compressor to be varied.

[0013] In the variable displacement swash plate type compressor, since athrough bore centrally formed at the swash plate 7 must regulate radialmovement of the swash plate 7 with respect to the drive shaft 5 and alsomust allow stable axial movement of the swash plate 7 while axiallysliding along the drive shaft 5, an inner surface of the through boremust accommodate variation of an inclined angle of the swash plate 7with respect to the drive shaft 5 on the one hand and must have a shapecapable of stably supporting the drive shaft 5 under the condition thatthe swash plate 7 is inclined at a predetermined angle on the otherhand.

[0014] To this end, the conventional compressor has a structure forsupporting a swash plate wherein a sleeve 20 is slidably inserted overthe drive shaft 5, and the sleeve 20 is inserted into the through boreof the swash plate 7 having a spherical inner surface, so that thespherical sleeve 20 comes into contact with the spherical inner surfaceof the swash plate 7, as illustrated in FIG. 1.

[0015] However, such a conventional structure for supporting a swashplate of a variable displacement swash plate type compressor hasdisadvantages in that it is difficult to achieve machining precision forspherical contacting surfaces of the sleeve 20 and particularly tomachine the inner surface of a journal 30 in a spherical shape so as toexactly meet the outer surface of the sleeve. Furthermore, though thespherical contacting portions of the sleeve 20 and the inner surface ofa journal 30 must be adhesively provided with oil mist contained inrefrigerant to assure lubrication effect, oil mist experiencesdifficulty in flowing between and adhering to the spherical contactingportions because the through bore is in close contact with an outersurface of the sleeve 20.

[0016] In order to overcome the above-mentioned problems, JapanesePatent Laid-Open No. 11-125176 (published on May 5, 1999) discloses astructure for supporting a swash plate having a sleeve 20 mounted on adrive shaft 5 and a journal 30 mounted on the sleeve 20 and inserted ina through bore of a swash plate (not shown) characterized in that thesleeve 20 is formed at its diametrically opposite portions with a pairof parallel flat surfaces 25, and the journal 30 is formed at itsthrough bore with a pair of flat surfaces 35 corresponding to the flatsurfaces 25 of the sleeve 20, the flat surfaces 25 and 35 of the sleeve20 and the journal 30 being slidably in contact with each other, thesleeve 20 and the journal 30 being coupled at their flat surfaces 25 and35 to each other by means of pins 40, as shown in FIGS. 1 and 2 of theaccompanying drawings.

[0017] However, such a conventional structure for supporting swash platedisclosed in the publication still has a problem in that the sleeve 20and the journal 30 must be formed with flat surfaces 25 and 35,respectively, and the flat surfaces 25 and 35 must be precisely machinedfor sliding contact therebetween. In addition, though improvement ofrubrication effect can be somewhat anticipated because the contactportions between the flat surfaces of the sleeve 20 and the journal 30are broadened toward a crank chamber, the improvement of lubricationeffect is limited due to the flat surfaces slidably contacting with eachother.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

[0018] Accordingly, the present invention has been made keeping in mindthe above problems occurring in the prior art, and an object of thepresent invention is to provide a structure for supporting a swash plateof a variable displacement swash plate type compressor adapted tofacilitate a machining operation for a sleeve and a journal withouthigh-precision processing.

[0019] Another aspect of invention provides a structure for supporting aswash plate of a variable displacement swash plate type compressor whichdoes not have slide contacting portions, thereby enabling lubricationtherebetween to be unnecessary.

[0020] One embodiment of the invention provides a structure forsupporting a swash plate of a variable displacement swash plate typecompressor comprising: a spherical sleeve mounted on the drive shaft; ajournal having a cylindrical bore for allowing the journal to be mountedon an outer surface of the sleeve, and inserted in the swash plate; anda pair of pins adapted to connect the journal to the sleeve and to allowthe journal to be turned with respect to the sleeve. The sleeve isshaped such that its external diameter is smaller than an internaldiameter of the journal (or a diameter of the cylindrical bore), so thata predetermined gap is provided therebetween. Surfaces of a pair of pinsand the sleeve tightly contact each other. Furthermore, each diameter ofpin sections to be connected with the journal and diameter of pinsections to be connected with the sleeve may be different from eachother. In this case, it is preferred that diameter of pin section to beconnected with the journal is larger than that of pin section to beconnected with the sleeve. For example, the pin section to be connectedwith the sleeve may has a cone shape. Furthermore, each of pin sectionsto be connected with the journal has threaded portion.

[0021] Another embodiment of the invention provides an apparatuscomprising; a sleeve having an outer surface, a first through-hole and asecond through-hole substantially perpendicular to the firstthrough-hole; and a journal having a surface defining a firstthrough-hole, the journal further having a second through-holesubstantially perpendicular to the first through-hole of the journal. Inaddition, at least a part of the sleeve is located within the firstthrough-hole of the journal in a way that the second through-holes ofthe sleeve and journal are arranged to receive a pin, and the surface ofthe journal is separated from the outer surface of the sleeve with a gapin a cross section where the second through-holes of the sleeve andjournal are formed. The gap is from about 0.025 to about 1 mm, or fromabout 0.05 to about 0.5 mm, or from about 0.075 to about 0.25 mm. Thesecond through-holes of the sleeve and journal have different diameters.The diameter of the second through-hole of the journal is larger thanthat of second through-hole of the sleeve. The second through-hole ofthe sleeve has a cone shape. The second through-hole of the journal hasa saw tooth shape.

[0022] Another embodiment of the invention provides a compressorcomprising the above apparatus.

[0023] Still another embodiment of the invention provides an airconditioner comprising the above compressor.

[0024] Yet another embodiment of the invention provides an apparatuscomprising a sleeve having an outer surface, a first through-hole and asecond through-hole substantially perpendicular to the firstthrough-hole; and a journal having a surface defining a firstthrough-hole, the journal further having a second through-holesubstantially perpendicular to the first through-hole of the journal. Inaddition, at least part of the sleeve is located within the firstthrough-hole of the journal in a way that the second through-holes ofthe sleeve and journal are arranged to receive a pin, and apredetermined sized gap is provided between the outer surface of thesleeve and the surface of the journal such that the outer surface of thesleeve does not contact the surface of the journal, wherein the gap isprovided in a cross section where the holes of the sleeve and thejournal are formed. The gap is from about 0.025 to about 1 mm, or fromabout 0.05 to about 0.5 mm, or from about 0.075 to about 0.25 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

[0026]FIG. 1 is a longitudinal cross-sectional view showing a variabledisplacement swash plate type compressor disclosed in Japanese patentLaid-open No. H 11-125176.;

[0027]FIG. 2 is a longitudinal cross-sectional view showing a structurefor supporting a swash plate of the variable displacement swash platetype compressor shown in FIG. 1.;

[0028]FIG. 3 is a longitudinal cross-sectional view showing a structurefor supporting a swash plate of a variable displacement swash plate typecompressor, according to an embodiment of the invention;

[0029]FIG. 4 is a cross-sectional view of FIG. 3; and

[0030]FIGS. 5a to 5 d are cross-sectional views similar to FIG. 4, whichshow various embodiment of the invention.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

[0031] Reference now should be made to the drawings, in which the samereference numerals are used throughout the different drawings todesignate the same or similar components.

[0032]FIG. 3 is a longitudinal cross-sectional view showing a structurefor supporting a swash plate of a variable displacement swash plate typecompressor according to an embodiment of the invention, FIG. 4 is across-sectional view of FIG. 3, and FIGS. 5a, 5 b, 5 c and 5 d are viewssimilar to FIG. 4, showing another embodiments of the invention.

[0033] As shown in FIGS. 3 and 4, a structure for supporting a swashplate of a variable displacement swash plate type compressor accordingto the invention includes a spherical sleeve 100 mounted on a driveshaft 5, a journal 200 mounted on an outer surface of the sleeve 100 andinserted in a swash plate (not shown), and a pair of pins 300 adapted toconnect the sleeve 100 and the journal 200 and to allow the journal 200to be rotated with respect to the sleeve 100.

[0034] The sleeve 100 is formed at its diametrically opposite portionswith pin holes 120 for receiving the pins 300. The journal 200 is alsoformed with pin holes 220 at positions corresponding to the pin holes120 of the sleeve 100. The pins 300 are also inserted in the pin holes220 of the journal 200. The journal 20 is provided at its outer surfacewith a threaded portion 230 for being engaged with a threaded portion ofa swash plate.

[0035] An internal diameter (D2) of the journal 200, i.e., a diameter ofa cylindrical bore 210 is shaped to be a little larger than Maximumexternal diameter (D1) of the sleeve 100.

[0036] When considering the exactness and easiness of machining thesurface of the outer surface of the sleeve and the inner surface of thejournal as well as considering stable rotational performance of theswash plate not trembled while acquiring any degree of inclinationthereof, a range of distance between these two diameters (D1, D2) isabout 0.025 mm to about 1 mm. A preferable range of distance between D1and D2 is about 0.05 mm to about 0.5 mm. A more preferable range ofdistance between D1 and D2 is about 0.075 mm to about 0.25 mm.

[0037] As a result, as shown in FIGS. 3 and 4, a predeterminedgap(distance between diameters D1, D2)400 is formed between the outersurface of the sleeve 100 and an inner surface of the cylindrical bore210 of the journal 200.

[0038] The pins 300 are vertically inserted into the drive shaft 5through the pin holes 120 and 220 of the sleeve 100 and the journal 200to rotatably connect the journal 200 to the sleeve 100. At this point,where the pins 300 inserted in the pin holes are completely inserted inthe pin holes not to be protruded outside, a swash plate can be easilycoupled to the journal.

[0039] The pins 300 may include such common cylindrical pins as pinsshown in FIGS. 3 and 4, and such pins having various shapes as pinsshown in FIGS. 5a to 5 d. In addition to that, pins having any shapescapable of rotatably connecting the journal 200 to the sleeve 100 can bealso used. Among the pins shown in FIGS. 5a to 5 d, the pins 300 shownin FIGS. 5a and 5 c have two cylindrical parts having diametersdifferent from each other. That is, a diameter of an inner cylindricalpart to be inserted in the sleeve 100 is smaller than that of an outercylindrical part to be inserted in the journal 200. Pins 300 shown inFIG. 5b have threaded portions at their outer parts to be inserted inthe journal 200 to securely support the journal 200. In the pins shownin FIG. 5b, an inner part of the pin 300 is not provided with a threadedportion to assure smooth sliding motion of the journal 200. Pins 300shown in FIG. 5d have the cone-shaped inner parts.

[0040] In fabrication of the structure for supporting a swash plateaccording to the invention, the sleeve 100 is first inserted into thecylindrical bore 210 of the journal 200. Subsequently, the pin holes 120of the sleeve 100 are aligned with the pin holes 220 of the journal 200,and then the pins 300 are inserted into the pin holes 120 and 220.Thereafter, the outer threaded portion 230 of the journal 200 is engagedwith the mating threaded portion of the swash plate. The swash plateassembly fabricated in this way is finally mounted on the drive shaft 5.

[0041] Since the external diameter of the sleeve 100 is shaped to besmaller than the internal diameter of the journal 200, a predeterminedgap is formed therebetween, and the sleeve 100 and the journal 200 areconnected to each other only by the pins 300.

[0042] The structure for supporting a swash plate constructed asdescribed above is designed to enable an incline angle of the swashplate with respect to the drive shaft to be easily controlled bydifferential pressure between a crank chamber and an exhaust chamber.Since the sleeve 100 and the journal 200 are connected to each other bymeans of the pins 300, the journal does not slide on the outer surfaceof the sleeve 100 but rotates about the pins 300.

[0043] Since a journal according to the prior art is in close contactwith a sleeve, it is difficult to achieve lubrication between thejournal and the sleeve. However, since a predetermined gap is providedbetween the sleeve and the journal, additional lubrication therebetweenis not necessary.

[0044] Furthermore, though the contacting surfaces of the journal andthe sleeve according to the prior art must be precisely machined, aprecise machining of the facing surfaces of the journal and the sleeveaccording to the invention are not necessary because a predetermined gapis present between the journal and the sleeve.

[0045] As described above, according to the present invention, since asleeve and a journal are not in contact with each other but connected toeach other by means of pins, a precise machining operation for facingsurfaces of the sleeve and the journal and an additional machiningoperation for flat surfaces are not necessary. Therefore, the sleeve andthe journal can be easily produced. Furthermore, since the sleeve andthe journal are not in contact with each other, lubrication therebetweenis not necessary.

[0046] Although preferred embodiments of the present invention have beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

What is claimed is:
 1. A structure for supporting a swash plate in such a manner that an incline angle of the swash plate can be controlled with respect to a drive shaft, comprising: a sleeve mounted on the drive shaft; a journal having a bore for allowing the journal to be mounted on an outer surface of the sleeve, and inserted in the swash plate; and a pair of pins adapted to connect the journal to the sleeve and to allow the journal to be turned with respect to the sleeve; wherein an outer surface of the sleeve is smaller than a surface of the bore, so that a predetermined gap is provided therebetween.
 2. A structure for supporting a swash plate of a variable displacement swash plate type compressor according to claim 1, wherein surfaces of said pins and said sleeve tightly contact each other.
 3. A structure for supporting a swash plate of a variable displacement swash plate type compressor according to claim 1, wherein each diameter of said pin sections to be connected with the journal and diameter of said pin sections to be connected with the sleeve are different from each other.
 4. A structure for supporting a swash plate of a variable displacement swash plate type compressor according to claim 3, wherein the diameter of the pin section to be connected with the journal is larger than that of the pin section to be connected with the sleeve.
 5. A structure for supporting a swash plate of a variable displacement swash plate type compressor according to claim 3, wherein said pin section to be connected with the sleeve has a cone shape.
 6. A structure for supporting a swash plate of a variable displacement swash plate type compressor according to claim 1, wherein each of said pin sections to be connected with the journal has a threaded portion.
 7. An apparatus, comprising; a sleeve having an outer surface, a first through-hole and a second through-hole substantially perpendicular to the first through-hole; and a journal having a surface defining a first through-hole, the journal further having a second through-hole substantially perpendicular to the first through-hole of the journal; wherein at least part of the sleeve is located within the first through-hole of the journal in a way that the second through-holes of the sleeve and journal are arranged to receive a pin, and wherein the surface of the journal is separated from the outer surface of the sleeve with a gap in a cross section where the second through-holes of the sleeve and journal are formed.
 8. The apparatus of claim 7, wherein the gap is from about 0.025 to about 1 mm.
 9. The apparatus of claim 7, wherein the gap is from about 0.05 to about 0.5 mm.
 10. The apparatus of claim 7, wherein the gap is from about 0.075 to about 0.25 mm.
 11. The apparatus of claim 7, wherein the second through-holes of the sleeve and journal have different diameters.
 12. The apparatus of claim 11, wherein the diameter of the second through-hole of the journal is larger than that of second through-hole of the sleeve.
 13. The apparatus of claim 7, wherein the second through-hole of the sleeve has a cone shape.
 14. The apparatus of claim 7, wherein the second through-hole of the journal has a saw tooth shape.
 15. The apparatus of claim 7, wherein the apparatus is included in a compressor.
 16. The apparatus of claim 15, wherein the apparatus is included in an air conditioner.
 17. An apparatus, comprising; a sleeve having an outer surface, a first through-hole and a second through-hole substantially perpendicular to the first through-hole; and a journal having a surface defining a first through-hole, the journal further having a second through-hole substantially perpendicular to the first through-hole of the journal; wherein at least a part of the sleeve is located within the first through-hole of the journal such that the second through-holes of the sleeve and journal are arranged to receive a pin, and wherein a predetermined sized gap is provided between the outer surface of the sleeve and the surface of the journal such that the outer surface of the sleeve does not contact the surface of the journal, wherein the gap is provided in a cross section where the holes of the sleeve and the journal are formed.
 18. The apparatus of claim 17, wherein the gap is from about 0.025 to about 1 mm.
 19. The apparatus of claim 17, wherein the gap is from about 0.05 to about 0.5 mm.
 19. The apparatus of claim 17, wherein the gap is from about 0.05 to about 0.5 mm.
 20. The apparatus of claim 17, wherein the gap is from about 0.075 to about 0.25 mm. 